Not applicable.
The present invention generally relates to the field of clean room-like environments and, more particularly, to a material delivery system for such environments.
Many manufacturing or assembly processes require an environment which is free of particulates or other contaminants to at least a certain degree. Clean rooms have long been used in the semiconductor industry for the processing of wafers from which semiconductor devices are formed. Other industries which have used clean rooms include computer disk drive manufacturers. Certain disk drive parts are manufactured in a clean room environment, while other parts are manufactured and then cleaned prior to entry into a clean room for incorporation into some type of an assembly within the clean room (e.g., an actuator arm assembly).
One alternative to clean rooms which has been used at least in the computer disk drive industry is a so-called minienvironment. Minienvironments effectively are a self-contained unit which may be disposed within or outside of a clean room and which provide clean room-like air qualities. A representative example of a minienvironment is disclosed in U.S. Pat. No. 5,487,768 to Zytka et al., which is owned by the assignee of this patent application, and which is incorporated by reference in its entirety herein. Generally, a minienvironment is an enclosure of sorts which has its own forced air system for delivering filtered air into the noted enclosure. Various types of access may be provided to the minienvironment and through which this air may be discharged along with any particulates or other contaminants contained therein. These accesses or fluid interconnections with the surrounding environment are typically disposed on a lower portion of the minienvironment, and the filtered air is typically introduced into the minienvironment in an upper portion thereof.
Smaller-sized openings may be provided in the minienvironment""s enclosure to allow an operator to dispose his or her arms therethrough to retrieve parts and/or to execute some type of operation (e.g., assembly) within the minienvironment. Only the operator""s hands and possibly a portion of the operator""s arms need to meet certain cleanliness requirements with this type of minienvironment. It should be appreciated that these types of minienvironments thereby do not provide for total isolation from the surrounding environment, but instead rely on a higher air pressure within the minienvironment""s enclosure to keep particulates and other contaminants which may exist in the surrounding environment from flowing into the minienvironment through the noted fluid interconnections. The above-noted reference to an xe2x80x9cenclosuresxe2x80x9d for a minienvironment would thereby include a shroud, hood, or the like which does not provide for a total enclosure (e.g., a gap may exist along a lower portion of a sidewall of the minienvironment). Some minienvironments may include a glove box or the like to further maintain the cleanliness within the minienvironment and for the above-noted types of purposes. Still other minienvironments have no access for operations personnel during normal operations within the minienvironment, but instead rely on robotic devices within the minienvironment to perform the desired operation(s) therewithin. In both of these later instances, there may be a total isolation of the interior of the minienvironment from the surrounding environment.
There are rather significant costs associated with the operation of both clean rooms and minienvironments. Simply put, the various actions which are undertaken in order to maintain the desired level of cleanliness often come at a rather significant financial cost. Both personnel and all other materials (e.g., parts to be used in an assembly being executed in the clean room/minienvironment) which enter the clean room or the minienvironment must be within the desired cleanliness level. U.S. Pat. Nos. 5,713,791 and 5,344,365 both address rather extravagant systems/methods directed to the transfer of materials to/from/within a clean room environment. So-called xe2x80x9cclean cartsxe2x80x9d have also been used to transfer materials from outside a clean room to a location therein. Known clean carts are simplistically a box with an access door on a side thereof (i.e., the top is non-removable in these units). Cleaned parts are loaded into this xe2x80x9cboxxe2x80x9d through the access door. Filtered air is simultaneously blown into the xe2x80x9cboxxe2x80x9d during loading through this access door as well. All intended discharges from within the xe2x80x9cboxxe2x80x9d at this time are also through this same access door as there are no other designed perforations in the clean cart. Once the clean cart is loaded, the door is closed to seal the interior of the same and it may then be wheeled into the clean room. Typically these clean carts are parked next to a station which uses the parts contained therein in some manner.
Numerous disadvantages exist in relation to known clean carts. One is that these clean carts consume floor space which in some cases may be at a premium. Another is that the operator must manually retrieve parts from the clean cart and provide the same to the subject workstation. Often this involves certain repetitive motions which may subject the operator to injury over time. For instance, an operator positioned on a chair at a minienvironment may have to rotate 90xc2x0 and bend over to access the parts contained within the clean cart, and thereafter rotate back to the minienvironment with the parts in hand (typically on a tray) to position them into the minienvironment. The alternative would be for the operator to get up and walk over to the clean cart which not only wastes valuable time, but possibly means positioning the clean cart at a location where there may be unanticipated impacts between the clean cart and personnel which would be undesirable in a number of respects.
The present invention generally relates to a material delivery system and, more particularly, to a material delivery system for use with a workstation in a xe2x80x9ccleanxe2x80x9d or filtered environment, such as a clean room or a minienvironment. One particularly desirable application for the present invention is for use in the assembly of computer disk drives.
A first aspect of the present invention generally relates to controlling the movement of an elevator in a material delivery system of the above-described type. A plurality of containers (e.g., a tray having a plurality of disk drive components stored therein), may be loaded on the elevator, either directly or through one or more intermediate structures. The elevator may be moved to position one of the containers for removal in a desired manner at the work station where the material delivery system of the first aspect is incorporated. One way to accomplish this movement of the elevator is to monitor for the presence of a container at least at one vertical position, and then to use the information to move the elevator in a predetermined manner.
Various refinements exist of the features noted above in relation to the first aspect of the present invention. Further features may also be incorporated in the present invention as well. These refinements and additional features may exist individually or in any combination. The work station that incorporates the first aspect of the present invention may include a tabletop or other work surface, on which one or more processing/assembly operations are performed in the filtered environment. The material delivery system may incorporate a number of features to reduce the potential for affecting the cleanliness level in the filtered environment. For instance, the material delivery system may include an upper support that is disposed at least generally at the same elevation as the work surface of the work station which incorporates the material delivery system of the first aspect. This upper support would then include a cavity that is aligned with the elevator to allow the plurality of containers to be loaded on and removed from the elevator. Multiple perforations may be incorporated on this upper support of the material delivery system so as to not adversely affect the downwardly directed flow that is typically used in filtered environments to maintain desired cleanliness levels. A platform on which the containers are stacked also may include a plurality of perforations for this same reason.
Movement of the elevator is again controlled by monitoring for the presence of a container at least at one vertical position in the first aspect. Any appropriate sensor for detecting the presence/absence of a container may be used. That is, a movement of the elevator may be initiated based upon a determination that a container is disposed at a certain vertical position. Conversely, a movement of the elevator may be initiated based upon a determination that a container is not disposed at a certain vertical position. Therefore, the xe2x80x9cpresencexe2x80x9d of a container in accordance with the subject first aspect includes both of these situations. The direction in which the elevator is moved may be based upon a determination as to whether a container is or is not disposed at a certain vertical position as well. Multiple sensors may also be used to control the movement of the elevator. One of these sensors may control the upward movement of the elevator, while the other of these sensors may control the downward movement of the elevator.
One way to control the movement of the elevator of the material delivery system in accordance with the first aspect of the present invention is to monitor for the presence of a container at two different vertical positions. Both of these vertical positions may be located beyond an upper end of the material delivery system through which containers are directed for unloading. The elevator also may be moved in opposite directions in response to whether a container has been detected at these two different vertical positions. That is, the presence or absence of a container at one of these vertical positions may result in a downward movement of the elevator, while the presence or absence of a container at the other of these vertical positions may result in an upward movement of the elevator. For example, assume that first and second vertical positions are monitored for the presence of a container, with the second vertical position being at a higher elevation than the first vertical position. The elevator may be directed to move in a downward direction if a container is detected at the second vertical position, while the elevator may be directed to move in an upward direction if no container is detected at the first vertical position.
Controlled movement of the elevator in accordance with the first aspect may also be used in loading and unloading the elevator. Consider the case where the material delivery system is xe2x80x9cempty.xe2x80x9d Typically the elevator will be at its uppermost position in this case through its controlling logic. A first container may be placed on the elevator and may occupy the first vertical position. Since no container is disposed at the second vertical position, the elevator will not be driven in a downward direction. Since there is a container disposed at the first vertical position, the elevator will not be driven in an upward direction. That is, if a container is detected at the second vertical position, the elevator will move down one increment, while if a container is not detected at the first vertical position, the elevator will move up one increment. A second container may then be placed on top of the first container. A container in this case will be disposed at the second vertical position, namely the second container. Therefore, the elevator will be lowered one increment, such that the second container will now be located at the first vertical position. This loading protocol may continue until the material delivery system is fully loaded, or until the desired number of containers have been loaded. It should be appreciated that the containers need not be placed on the elevator one at a time. Multiple containers could be simultaneously loaded on the elevator. In this case, if a container is detected at the second vertical position, the elevator will move down one increment. If after this downward incremental movement a container is still detected at the second vertical position, the elevator will move down yet another increment. This will continue until no container is detected at the second vertical position, which will correspond with the material delivery system of the first aspect being in a fully loaded state.
Continuing with the above-noted example now in relation to unloading the material delivery system of the first aspect, the absence of a container in the first vertical position is controlling in relation to the movement of the elevator. Preferably the first vertical position corresponds with the elevator being positioned to dispose the xe2x80x9cuppermostxe2x80x9d container in the material delivery system at least at generally the same elevation as the work surface of the workstation that incorporates the material delivery system of the first aspect. In the above-noted example, the second container was stacked on top of the first container. Assume that the second container is disposed at the first vertical position such that the first container is disposed at a lower elevation or within the material delivery system. When the second container is removed from the elevator, there will no longer be any container disposed at the first vertical position. This will be detected and cause the elevator to move in an upward direction one vertical increment such that the first container will now be disposed at the first vertical position. This protocol will continue until the material delivery system has been completely unloaded Preferably, the first aspect somehow limits the extent of the upward travel of the elevator (e.g., so as to not attempt to move up one more increment after the last container has been removed from the material delivery system). For instance, the upper extreme of the elevator travel could at least generally correspond with the location of the elevator when a container thereon is at the first vertical position. Other options exist. For instance, the material delivery system could allow the elevator to proceed in an upward direction a certain amount after the last container was removed from the elevator through another sensor. This could be the xe2x80x9cstartingxe2x80x9d position for the elevator in a loading procedure as well.
A second aspect of the present invention generally relates to a quick connect/disconnect feature for an elevator of a material delivery system The material delivery system generally includes a housing having an open upper end and a hollow interior. A first platform is disposed within the housing for supporting at least one and typically a plurality of containers. An elevator is interconnected with the housing in a manner so as to be able to raise the first platform for the removal of any containers stacked thereon at the workstation that incorporates the material delivery system of the second aspect. A desirable interconnection is established between the housing and the elevator which preferably does not require any tooling for either installation or removal. In this regard, a pair of mounting slots are provided on a pair of opposite sides of the housing of the material delivery system, and the elevator includes a mounting assembly that has a pair of mounting pins on a pair of opposite sides thereof. The mounting pins are removably received in the mounting slots on the housing to provide the desired type of interconnection.
Various refinements exist of the features noted above in relation to the second aspect of the present invention. Further features may also be incorporated in the second aspect of the present invention as well. These refinements and additional features may exist individually or in any combination. For instance, the mounting slots may be oriented such that gravity alone retains the mounting pins of the elevator within the slots. Each of the mounting slots may slope downwardly at an angle such that the corresponding mounting pin will be disposed at the lowermost extreme of its corresponding mounting slot. One way for introducing the mounting pins into their corresponding mounting slot is to contour each slot to first extend at least generally upwardly, and then downwardly therefrom. In this case, the mounting pins on the elevator would first be aligned with their corresponding mounting slot, then moved in an at least generally upward direction, and then moved in an at least generally downward and lateral direction to complete the interconnection of the elevator to the housing.
A third aspect of the present invention generally relates to allowing an elevator of a material delivery system to be replaced without having to unload any containers from the material delivery system. In this regard, the material delivery system includes a housing having an open upper end through which containers may be removed from the hollow interior of the housing. A platform support exists somewhere within the hollow interior of the housing. The platform support may be part of the housing or separately attached thereto, but nonetheless allows for the passage of containers therethrough via movement of an elevator. A container platform may be disposed on this platform support, and a plurality of containers may be stacked on this container platform. An elevator platform travels through the hollow interior of the housing and may engage the lower extreme of the container platform to move the container platform in an at least generally upward direction to present one or more containers at a desired elevation (e.g., at least generally coplanar with a work surface of a work station that incorporates the third aspect). Therefore, the container platform is lifted off of the platform support by the elevator platform.
Various refinements exist of the features noted above in relation to the third aspect of the present invention. Further features may also be incorporated in the third aspect of the present invention as well. These refinements and additional features may exist individually or in any combination. The use of a container platform and a separate elevator platform allows the elevator to be disconnected from the housing without having to first unload any containers from within the housing. The elevator may be moved in an at least generally downward direction. At a certain point in time in this downward movement, the elevator platform will become disengaged from the container platform. At this time the container platform will then be supported by the platform support that is associated with the housing of the material delivery system of the third aspect, and not the elevator. Therefore, the elevator may be disconnected from the housing without having to unload any of the containers. Those features discussed above in relation to the connection between the housing and the elevator in the second aspect may be utilized by the third aspect as well.
Both the container platform and the elevator platform may include a plurality of perforations, which facilitates the use of the material delivery system of the third aspect in a filtered environment that uses an at least generally downwardly directed flow to maintain a desire degree of cleanliness. Control of the movement of the elevator in the third aspect may be in the manner discussed above in relation to the first aspect of the present invention.